Plug-in ionizer



FIG. 1 is a perspective view of a plug-in ionizer showing our new design;

FIG. 2 is a front view thereof;

FIG. 3 is a right side view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a left side view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof. 

The ornamental design for a plug-in ionizer, as shown. 